
using System;

class Teste
{

static void Troca(ref string s, ref string t)
{
	string tmp=s; 
	s= t;
	t = tmp;
}

static void Main()
{
string a = "passo", b ="coelho";
Console.WriteLine(a+b);
Troca(ref a, ref b);
Console.WriteLine(a+b);
}
}
